Personally - I would use it to either capture leads (opt-in leads to eBook download) or as a OTO for your dieting product.
From a marketing standpoint, I would sell a "program" or "system" as opposed to an eBook.
Even if it is a collection of eBooks (heck - break them into reports or modules) - people are more willing to part with their $47 on ClickBank if they are buying a "program" or a "system".